Navigation Links
Even healthy lungs labor at acceptable ozone levels

Ozone exposure, even at levels deemed safe by current clean air standards, can have a significant and negative effect on lung function, according to researchers at the University of California Davis.

"The National Ambient Air Quality Standard (NAAQS) for ozone was recently revised to set lower limits for ozone concentrations. Our research indicates that the threshold for decrements in ozone-induced lung function in healthy young subjects is below this standard," said Edward Schelegle, Ph.D., of the University of California Davis. "Specifically, we found that 6.6 hours exposure to mean ozone concentrations as low as 70 parts per billion have a significant negative effect on lung function, even though the current NAAQS standards allow ozone concentrations to be up to 75 parts per billion (ppb) over an eight-hour period."

The results we published in the August 1 issue of the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.

To test whether mean ozone concentrations above and below the new standard induce lung function decrements and to further study the time-course of these decrements, Dr. Schelegle and colleagues recruited 31 healthy nonsmoking individuals to participate in 6.6-hour sessions during which they were exposed to ozone at 60, 70, 80 or 87 ppb or filtered air while undergoing six 50-minute bouts of moderate exercise followed by 10-minute breaks. A 35-minute lunch break separated the third and fourth bouts of exercise.

Lung function for each subject was assessed before, during and after exposure, and each individual answered a questionnaire evaluating their subjective symptoms. Of the four levels of ozone concentration tested, Dr. Schelegle and colleagues found significant decrements in both lung function and subjective respiratory symptoms at 70 ppb and above, beginning at 5.6 hours after exposure.

"These data tells us that even at levels currently below the air quality standard, healthy people may experience decreased lung function after just a few hours of moderate to light exercise such as bicycling or walking," said Dr. Schelegle. "While these changes were fully reversible within several hours, these findings highlight the need to study susceptible individuals, such as asthmatics, at similar ozone concentrations and durations of exposure. These studies are needed to better understand the acute rise in hospitalizations that often occur in conjunction with high-ozone periods."

The study also supports the previously reported smooth dose-response curve associated with ozone. That is, the higher the level of ozone, the greater the decrease in lung function. However, the healthy subjects in the study showed a marked individual variability in their responses to ozone, with a few exhibiting strong sensitivity to ozone concentrations. What causes some individuals to respond strongly while others do not is still unknown.

"Schelegle and colleagues do not, nor did they seek to explain the determinants of susceptibility in young, healthy adults," noted James S. Brown, of the U.S. Environmental Protection Agency, in an accompanying editorial. "Only with continued research efforts will we be able to better characterize the susceptibility in some healthy individuals, to the effects of short-term ozone exposures."

Dr. Schelegle also notes the need for further research to further elucidate the precise mechanisms that determine an individual's ozone responsiveness in both healthy and susceptible populations. "Understanding how these mechanisms change with repeated daily exposures is critical, especially as ambient ozone levels are often elevated several days in a row," Dr. Schelegle said.


Contact: Keely Savoie
American Thoracic Society

Related medicine news :

1. Penn study finds pro-death proteins required to regulate healthy immune function
2. UCLA researchers identify markers that may predict diabetes in still-healthy people
3. Air pollution linked to cardiovascular risk indices in healthy young adults
4. Top Tips to Enjoy Healthy Latin Food Without Losing the Taste (Recipe)
5. Finicky Felines Award Four Stars to New Wellness(R) Healthy Indulgence Everyday Entrees
6. Keeping Kids Healthy and Fit: The New York Kids Club Launches a Revolutionary New Fitness Program
7. LifeMasters Provides Tips for Maintaining a Healthy Blood Cholesterol Level
8. On September 7th Local Organizations Partner to Celebrate Healthy Steps
9. September is Healthy Aging Month
10. Children who learn heart healthy eating habits lower heart disease risk
11. FDA: Use the Nutrition Facts Label to Make Healthy Food Choices
Post Your Comments:
(Date:10/13/2017)... ... October 13, 2017 , ... Ellevate Network, the leading network ... advocate for action towards gender equality at their inaugural Summit in New York City ... and reached a social audience of over 3 million. To watch the Mobilize Women ...
(Date:10/13/2017)... Texas (PRWEB) , ... October 13, 2017 , ... Yisrayl ... this week that explains one of the most popular and least understood books in ... like cryptic and puzzling descriptions that have baffled scholars for centuries. Many have tossed ...
(Date:10/13/2017)... ... October 13, 2017 , ... ... Agile Software Development, has been awarded a contract by the Center for Medicare ... (BPA) aims to accelerate the enterprise use of Agile methodologies in a consistent ...
(Date:10/13/2017)... ... October 13, 2017 , ... “America On The Brink”: ... “America On The Brink” is the creation of published author, William Nowers. ... As a WWII veteran, he spent thirty years in the Navy. Following ...
(Date:10/12/2017)... ... October 12, 2017 , ... CitiDent ... sleep apnea using cutting-edge Oventus O2Vent technology. As many as 18 million ... by frequent cessation in breathing. Oral appliances can offer significant relief to about ...
Breaking Medicine News(10 mins):
(Date:10/2/2017)... 2017 Halo Labs announces the European launch of their ... HORIZON at MIBio 2017 in Cambridge, U.K ... matter in biopharmaceutical samples with unprecedented speed and sensitivity while using ... Backgrounded Membrane Imaging. ... subvisible particle analysis system ...
(Date:9/27/2017)... CAESAREA, Israel and NEW YORK , Sept. ... company with mobile health and big data solutions, today announced that its ... today. Please check your local TV listings for when The Dr. Oz ... ... ninth season this month. ...
(Date:9/22/2017)... DIEGO , Sept. 22, 2017 AVACEN ... medical device is now successfully helping those with the ... Fibromyalgia diagnosed Amanda in Essex, ... dressed and washing my hair, experiencing no sleep at ... in painful spasm… I cannot recommend [the AVACEN 100] ...
Breaking Medicine Technology: